Windows has a more intuitive and more comprehensive GUI than any Linux distro
Windows is a commercially successful OS, with excellent support, and software and hardware compatibility, despite not costing a dime to most of its users.
Windows has better creative software available, such as the Adobe Creative Suite, various video and audio editing suites, etc.
Microsoft Office is better than any other office suite (of course it's also available for other platforms, but not Linux, not without emulation)
Windows has a more intuitive drive naming convention.
The command line interface in Windows is easier to use, even though it's rarely used for everyday tasks.
Windows has more convenient accessory programs installed by default
Windows has more accessible logs and system information.
Windows is better documented than any Linux distro, its information all neatly organized and known where to be found.
I need not mention about games. Whether you like them or not is irrelevant.
I saved the best till last: Windows has Active Directory, centralizing user documents and personal settings, and security and group policy settings, something large organizations couldn't do without.
Until Linux has something like Active Directory and a GUI to rival Windows, it won't even be considered by large organizations, not even for free, and let's be honest, that's where a big chunk of the userbase and the money is.